Gas pipelines are used to transport compressed natural gas. One difficultly associated with transporting gas in a gas pipeline relates to the collection of fluids in low spots in the pipeline. The fluids are typically the result of condensate and may be water, liquid hydrocarbons or a mixture of both. Once the fluid level is high enough to block the flow of gas through the pipeline, then gas transport becomes less efficient. Consequently, pipeline owners periodically send trucks out to pipeline low spots so that the fluids can be evacuated. This method of fluid evacuation is costly and inefficient, e.g., the cost to deploy a truck for collection may be $200/day and may result in the recovery of only a half barrel of liquid. This recovery may be required as often as daily. Another method of fluid removal is via a pigging process. However, periodic pigging may not be possible due to line design, low pipe pressure, or prohibitive pipeline material.
Therefore, a need exists to evacuate fluids that is more cost efficient. In particular, a “continuous” fluid evacuation, i.e., fluid evacuation not requiring manual intervention via a deliquification by dip truck or pipeline pig will reduce costs and improve efficiency.
During oil and natural gas production and transportation processes, water, condensate and/or liquid hydrocarbons are separated from the oil or natural gas. If these fluids are collected and transferred to a tank or container that is open to the atmosphere, harmful compounds contained in the condensate/liquid hydrocarbon portion of the fluid mixture are allowed to enter the air when the condensate vaporizes at atmospheric pressure. These compounds entering the atmosphere are a huge issue with government environmental quality regulating agencies as well as natural gas well and oil and natural gas pipeline operators. There is equipment designed to recompress these vapors called vapor recovery units, but energy contained in the condensate is more valuable in a liquid state than in a gaseous state. There are also substantial costs associated with the vapor recovery process, which does not facilitate returning the vapors to a liquid, it only returns the vapors to a natural gas pipeline or natural gas pipeline related equipment.
Therefore, a need exists to collect, transfer and store these liquids under approximately the same pressures in which they were recovered from the oil or natural gas production or transportation equipment.
Natural gas wells are used to extract natural gas (comprised mostly of methane in its gaseous state) from the earth. One difficultly associated with the extraction of natural gas from the earth via a natural gas well, relates to the collection of fluids in the well bore. The fluids are typically water, hydrocarbons, or a mixture of both. Once the fluid level is high enough to block the flow of gas through the production tubing of the gas well, then gas extraction becomes much less efficient, or even impossible in certain conditions. Consequently, many well owners utilize a plunger lift that consists of a mechanical device that is periodically inserted into the tubing and allowed to drop through the fluid build up, to the bottom of the tubing. The well is then shut in which causes the gas pressure in the well bore to raise to the point in which it overcomes the weight of the fluid build up, the gas production line pressure, and the weight of the plunger itself. When this pressure point is reached, the well is then allowed to flow again, at which time the plunger begins to move upwards in the tubing, forcing the buildup of fluids, now on top of the plunger lift, toward the surface of the earth. Periodically and in certain conditions, the pressure that the well is capable of building on its own is insufficient to overcome the weight of the fluid buildup, and the plunger is unable to be recovered without other means of intervention in the process. The other means of recovering the plunger are sending a truck out to work the plunger up the tubing, a process called “swabbing”, or venting the natural gas in the tubing to atmosphere which lowers the pressure above the plunger, allowing it to return to the surface of the earth. Trucks are expensive to utilize, e.g., $170 per hour for as many as 20 to 30 hours. Venting natural gas to atmosphere results in loss of production, is dangerous, and is also detrimental to the environment
Therefore, a need exists to automatically assist in fluid evacuation and plunger lift recovery from the well bore.